Test automation has never been easier with Keysight i7090 automated inline test systems using Pathwave Test Executive for Manufacturing(PTEM). This series of test automation posts describes the simple commands and sequences that enable full control of the test operation while keeping the stringent automation safety interlocks as required in the automotive printed circuit board assembly (PCBA) lines.
Are you into test automation? Check out the series of test automation posts listed at the end of this article and let me know if you have any questions or comments.
Now, let us get to the final stage of the automated test cycle. Earlier posts bring you though the setup and configuration of the i7090 test system followed by the automated board transfer process. This post completes the cycle by sending the test results of the device under test (DUT) to the i7090 handler system and the release of the tested DUT to the downstream station.
Figure 1: Runtime sequences after test completion.
Testplan starts testing after the DUT is engaged onto the test fixture. In Figure 2, testplan executes the Handler_SetAllProbeDone test step to signal to the handler the completion of testing at the all-probe position. All-probe position is a press position where all the test probes on the fixture are in contact with the DUT. This position is used for in-circuit tests (ICT), and sometimes functional tests (FCT) as well if they are not sensitive to probe loading from the fixture. However, other FCT tests may require isolating the DUT from unnecessary test probes to keep good signal integrity during the tests. This requires the press to move into the long-probe position, which lifts the DUT upwards and disconnects away from standard length test probes on the fixture, leaving only longer-length probes in contact. Hence, the name long-probe position.
After Handler_SetAllProbeDone, the testplan may send the command to move the press from all-probe position to the long-probe position for FCT if needed. This process of testing a DUT with different test probe lengths is a “dual stage” test. It is a topic, and I will leave it for future discussion.
Figure 2: Testplan executes Handler_SetAllProbeDone at the end of test operation.
Next will be to send the test results to the handler. A DUT can be a single unit, or a panel made up of multiple units. A single DUT is straightforward as there is only one set of test results to manage. With multiple DUTs in a panel, one or more DUTs may fail while others pass in the same panel.
How does the handler manage the mixture of test results in a panel?
Regardless of the number of DUTs in a panel, the handler sees them as a single entity. The panel passes when all the DUTs in the panel pass and fails when any one of them fails. PTEM automatically combines the test results of every DUT and set the panel result to a system variable in the testplan. After the testplan sends the panel result to the handler, the handler transfers the panel downstream into pass or fail bins accordingly.
Keysight i7090 handler system can handle two DUTs or panels in one test cycle. It is possible to have two independent panels of DUT tested in one cycle. In this case, the handler expects to receive two sets of test results from the testplan after the test is completed. During the test, PTEM sets the results of each panel to the system variables FIELD.Panel1Result and FIELD.Panel2Result in real time. Test steps use these to stand for the result of each panel.
Figure 3: System variables holds the test results in real time and ready for testplan to use.
Handler_SetPanel1Result and Handler_SetPanel2Result test steps send the test results to the handler.
In Figure 3, Handler_SetPanel1Result uses the variable FIELD.Panel1Result as its parameter, and Handler_SetPanel2Result uses FIELD.Panel2Result accordingly. So, depending on whether you are running a single or dual-panel operation, your testplan will execute one or both test steps to send the results to the handler. Once the results are set, the transfer of the DUT to the downstream station will start automatically. Although there are two panels of DUT in the handler, the transfer operation stays in the singular mode, where one panel is transferred after the other. In this way, there is no need to configure the downstream station specifically to receive two panels at a time.
For the handler, this is the end of a test cycle. After the handler transfers the panels out, it waits for the next set of DUTs to be available and starts the next transfer cycle. This does not require any supervision from the testplan. The handler runs in this endless loop until it receives a stop command from the testplan, or the handler meets an error. For the testplan, the last step is to initialize the variables and reset them to their default values before returning to the start of the runtime test cycle loop.
Figure 4: Testplan resets system and user variables at the end of a cycle.
Reset Test Operations test step resets system variables like DUT serial numbers, DUT results and panel results to their default values. This step also increases the test count by one for the tracking of the total test cycle executed. There is no need to specify which system variables to reset. PTEM takes care of it automatically.
The Initialize Variables test step allows you to select any variables to include in the reset list. This includes system variables and user variables. The difference between them is that Initialize Variables lets you set what value to reset the variables to. Just select and drag the variables you like to set over to the left side of the table and specify the new value. This is much easier than resetting the user variables one by one using assignment steps.
Now let us summarize all the test steps and commands that we have discussed over the past few posts.
Table 1: Summary of test steps used in a typical automated test cycle.
The i7090 handler plugins in PTEM hold many more test steps that allow you detailed control over the handler movements in manual mode. Working with the programmable logic controller (PLC), the test steps in Table 1 let you program a basic test cycle easily without worrying about the details of sensors and actuators. This also ensures that that the handler movements are working within the safety interlocks of the PLC to safeguard the user and equipment.
You are welcome to contact me if you would like to get a copy of the testplan shared in this series of Keysight i7090 Test Automation with PTEM or if you have any questions regarding PTEM.
Stay safe and happy.